Field of the Invention
The present invention is generally directed to a cooler for granular products, such as pellets, and is more particularly directed to a discharge mechanism for a cooler of the type utilizing counter-flowing air through a hopper or bin to cool pelletized or particulate material therein. More specifically, a method and apparatus for discharging the particulate or pellets in the cooler intermittently interrupts the discharge flow of products through the use of swiveling gates positioned beneath outlet ports of the cooler.
Coolers are used in feed and food processing to cool pelletized or particulate products after they have been treated thermally, such as during pelleting, extrusion, drying, or other industrial processes.. One conventional type of cooler comprises a large bin. The feed or food material is introduced into the bin near the top, and is traditionally discharged into a hopper located beneath the bin. A fan at the top of the bin is used to draw a low volume of air having a high static pressure drop through the bottom of the bin, through the compacted feed or food material within the bin, and out the top. This counter-flowing air serves to cool the material.
The discharge area of coolers of this type traditionally have a series of fixed openings through which the cooled product may fall, usually into a hopper as described, or perhaps directly onto a conveyor or other mechanism for transferring the material to further processing stations or for packaging.
Cooler discharge mechanisms have previously been developed which periodically release feed or food material in the cooler through ports positioned at the bottom of the cooler. This is traditionally accomplished by a series of plates which are positioned so as to cover the discharge openings of the cooler, but which can be slid away from the opening to permit feed or food product to fall through the port. In other words, mechanisms have previously been developed which effectively form a horizontally oscillating slide gate discharge. With such discharge mechanisms, no product can flow when the plates are in the closed position, but when the plates are pulled away from the fixed openings, product can flow.
Removal of product dust from the cooler is particularly important between different uses of the cooler. For instance, after a first type of feed is cooled, such as chicken feed having certain antibiotics in the feed for chickens, a second application of the cooler, for instance for cooling pig feed, would necessitate removing any chicken feed dust from the cooler to prevent it from being mixed with the pig feed. In other words, dust is considered a contaminant, which can potentially be harmful to the persons or animals consuming the product.
There are numerous drawbacks associated with the discharge mechanisms described. One primary drawback of such discharge mechanisms is that the plates are slid horizontally away from the openings to permit product to discharge. However, when this is done, the plates slide along the bottom of the cooler, and namely the periphery of the fixed openings which, although serving to scrape product off of the plate and through the opening, causes wear on the plates. Additionally, since there is typically some product dust or small particulate in the product itself, it is virtually impossible to wipe all of the dust off of the plate as it opens. Moreover, in most applications it is not necessary to open the fixed openings entirely, but rather the plate is only moved so that a portion of the fixed opening is unobstructed. As a result, product tends to accumulate on the plate in proximity to the obstructed area of the opening, thereby adversely affecting material flow.
Accordingly, the need exists for a discharge mechanism for a cooler utilizing counter-flowing air which prevents product build-up and will allow complete discharge of product, including dust. The present invention overcomes the foregoing drawbacks and fills these and other needs.
Description of the Related Art